“The advice used to be hide under a desk, take cover. The advice changed,” Lanier says. “Fight your way out. Get out. Don’t wait and hide … If there’s a way for you to get out, get out.”

The New York Times reports other police departments in the country echo this advice.

Before the Columbine High School shootings, Lanier says D.C. police were trained to wait for a SWAT team when responding to shootings with hostages. Now, the training says don’t wait — the first three officers should go inside and take action.

But while public and private schools train students in lockdown procedures, there’s no training in movie theaters, shopping malls and many offices to deal with shootings.

Still, in desperate situations, there can be the bold and brave who might challenge a gunman.

“There are people who are going to stand up and they’re going to take action,” says Lanier. “There are some scenarios where if somebody has the opportunity to stand up and stop that loss of life and they feel they can do it, they should do it.”